The invention relates to a tool store for machine tools, particularly numerically controlled processing or machining machines wherein tools can be stored and arranged on a tool magazine and wherein tools can be removed and returned by means of a handling device. The invention also relates to a method for operating this tool store.
Tool stores are mainly used in machine tools for the numerically controlled machining of workpieces, particularly in machining centres. One known basic configuration of the tool store is the disk-like plate magazine, on whose circumference the tools, usually together with a tool holder, are arranged cylindrically or radially. When the tools are arranged radially, an increase in the number of the storage places can be obained by superimposing several such plate magazines in layer form, cf. e.g. German Pat. No. 1 912 369. In such a tool store, the tools are stored in axially displaceable blocks, with the aid of which the tools can be moved into a tool transfer position, where they can be removed from the magazine or returned to the same by the tool changer. However, this configuration has the disadvantage that a relatively large expenditure is involved in connection with the displaceable storage of the blocks and the displacement mechanism.
This disadvantage can be reduced by arranging the tools in several stages axially on a rotating drum and locating the tools with their longitudinal axis tangential to a circular path concentric to the cylinder, so that they can be removed and inserted by a gripper means. However, in this arrangement the number of tools arranged on the drum circumference is relatively small (Swiss Pat. No. 556, 712).
A second basic form of a tool store is the chain magazine, in which the tools are placed in parallel or at right angles to the rotation axes of a rotating chain drive. However, if the number of tool places of such a chain magazine is not sufficient, it necessary to set up one or more additional magazines on the machine tool. This arrangement requires a relatively large amount of space, as well as a relatively large expense for removing and returning the tools.
In addition, so-called surface stores are known in which the tools are arranged on a planar, usually vertical surface and are removed and returned by a gantry or portal loader. This arrangement can be used to have a large tool storage capacity and in addition each tool can be relatively rapidly reached by means of the portal loader, without moving the entire mass of tools, such as is the case with the plate or chain magazine. However, the large amount of space required is very disadvantages, because apart from its own surface area, each tool requires additional, unused access surfaces for the portal loader, so that the latter has to perform large displacements. This solution is also scarcely usable for multi-spindle machines, because the simultaneous removal of several tools from the surface store is problematical.